!explain via ❓ reaction: thread-reply with a 3-bullet TL;DR

When a user reacts ❓ on one of Pete's posts, fetch the article body,
ask Ollama for a 3-bullet summary, and post it as a threaded reply
rooted at the original story event. Per-process cooldown of 5min per
story keeps repeated reactions from re-summarizing.

- ingestion.FetchArticleBody: visible <p> text capped at 8000 chars
- classifier.OllamaClient.GenerateText: non-JSON variant
- storage.GetStoryByGUID: full row lookup
- matrix.PostThreadedReply: m.thread + m.in_reply_to fallback
- poster.SetReactionCallback: optional hook fired after recording
- New package: internal/explainer

main.go

@@ -11,6 +11,7 @@ import (
 
 	"pete/internal/classifier"
 	"pete/internal/config"
+	"pete/internal/explainer"
 	"pete/internal/ingestion"
 	"pete/internal/matrix"
 	"pete/internal/poster"
@@ -73,8 +74,10 @@ func main() {
 	// Create post queue
 	queue := poster.NewQueue(cfg.Posting, mx)
 
-	// Wire reaction handler
+	// Wire reaction handler + ❓ → summary hook
 	mx.SetReactionHandler(poster.HandleReaction)
+	exp := explainer.New(mx, ollamaClient)
+	poster.SetReactionCallback(exp.Handle)
 
 	// Set up graceful shutdown
 	ctx, cancel := context.WithCancel(context.Background())